Jean Tate
Definition of Velocity
[/caption] Velocity, in physics, is a vector quantity (it has both magnitude and direction), and is the time rate of…
Gravity Formula
The gravity formula that most people remember, or think of, is the equation which captures Newton's law of universal gravitation,…
Ephemerides
[/caption] Ephemerides is the plural form of ephemeris; one ephemeris, two (three, four, …) ephemerides. Why such a strange word?…
What is Space?
First, some simple answers: space is everything in the universe beyond the top of the Earth's atmosphere - the Moon,…
This Week’s astro-ph Preprints: Jean Tate’s Best Pick
It goes by the super-catchy (not!) title "A Catalog of MIPSGAL Disk and Ring Sources". I chose it, over 213…
Ripped to Shreds, Exoplanet Suffers Painful Death
[/caption] WASP-12b, discovered in 2008, is a real outlier among the 400 or so exoplanets discovered to date. Not that…
Nailing Down Goldilocks: What’s “Just Right” for Exo-Earths?
For Goldilocks, the porridge had to be not too hot, and not too cold … the right temperature was all…
Radio Waves
[/caption] Radio waves are electromagnetic waves, or electromagnetic radiation, with wavelengths of about a centimeter or longer (the boundary is…
Proton Mass
The mass of the proton, proton mass, is 1.672 621 637(83) x 10 -27 kg, or 938.272013(23) MeV/c2, or 1.007…
Better Late Than Never: Dwarf Galaxies Finally Come Together
[/caption] Have you heard of 'living fossils'? The coelacanth, the ginko tree, the platypus, and several others are species alive…